fix(build): resolve rewrites against externally injected pages too

Rewrites were computed from the locally globbed pages only, so pages
injected via the config were present in siteConfig.pages but never
entered the rewrites map.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/node/plugins/dynamicRoutesPlugin.ts

@@ -113,7 +113,7 @@ export async function resolvePages(
   )
   const finalPages = [...pages, ...externalPages].sort()
 
-  const rewrites = resolveRewrites(pages, siteConfig.userConfig.rewrites)
+  const rewrites = resolveRewrites(finalPages, siteConfig.userConfig.rewrites)
 
   Object.assign(siteConfig, {
     pages: finalPages,